Kinsale (/kɪnˈseɪl/ kin-SAYL; Irish: Cionn tSáile, meaning 'head of the brine') is a historic port and fishing town in County Cork, Ireland. Located approximately 25 km (16 mi) south of Cork City on the southeast coast near the Old Head of Kinsale, it sits at the mouth of the River Bandon, and has a population of 5,991 (as of the 2022 census) which increases in the summer when tourism peaks. The town is in a civil parish of the same name.

Kinsale is a holiday destination for both Irish and overseas tourists. The town is known for its restaurants, including the Michelin-starred Bastion restaurant, and holds a number of annual gourmet food festivals.

As a historically strategic port town, Kinsale's notable buildings include Desmond Castle (associated with the Earls of Desmond and also known as the French Prison) of c. 1500, the 17th-century pentagonal bastion fort of James Fort on Castlepark peninsula, and Charles Fort, a partly restored star fort of 1677 in nearby Summercove. Other historic buildings include the Church of St Multose (Church of Ireland) of 1190, St John the Baptist (Catholic) of 1839, and the Market House of c. 1600. Kinsale is in the Cork South-West (Dáil Éireann) constituency, which has three seats.

In January 1334, under a charter granted by King Edward III of England, the Corporation of Kinsale was established to undertake local government in the town.

The corporation existed for over 500 years until the passing of the Municipal Corporations (Ireland) Act 1840, when local government in Kinsale was transferred to the town commissioners who had been elected in the town since 1828. These Town Commissioners became the Kinsale Council under the Local Government (Ireland) Act 1898 and the Kinsale Town Council existed until 2014 when this layer of local government was abolished in Ireland as part of measures to reduce the budget deficit following the 2008 financial crisis (see Post-2008 Irish economic downturn). It returned two members to the Irish House of Commons prior to its abolition in 1800.

In its history, Kinsale has also important occasional links with Spain. In 1518 Archduke Ferdinand, later Emperor Ferdinand I, paid an unscheduled visit to the town, during which one of his staff wrote a remarkable account of its inhabitants.

In 1601, a Spanish military expedition to Ireland – the last of the Armadas launched against the Kingdom of England – landed in Kinsale in order to link with Irish rebel forces and attack England through Ireland. As a result, the battle of Kinsale took place at the end of the Nine Years War in which English forces, led by Charles Blount, 8th Baron Mountjoy, defeated the rebel Irish force, led by Hugh O'Neill, 2nd Earl of Tyrone and Red Hugh O'Donnell, two Gaelic princes from Ulster. The Irish forces were allied with the forces of King Felipe III of Spain, who was also King of Portugal and the Algarves.

In September 1607, a few years after this battle, the Flight of the Earls took place from Rathmullan in County Donegal in West Ulster in which a number of the native Irish aristocrats, including both Hugh O'Neill, 2nd Earl of Tyrone and Rory O'Donnell, 1st Earl of Tyrconnell, abandoned their lands and fled to Continental Europe. Shortly after the battle, James's Fort was built to protect the harbour. Completed by 1607, the central structure was a half-bastioned four-sided stone fortification, surrounded by pentagonal earthworks to a bastion fort or star-shaped fort design.